1. Field of the Invention
The present disclosure relates to a wireless communication device and method, especially to a wireless communication device and method capable of establishing peer-to-peer connections.
2. Description of Related Art
Wi-Fi Direct is a peer-to-peer connection technology developed and authenticated by Wi-Fi Alliance. This technology allows two wireless communication devices to connect with each other without any intermediate devices (e.g., a wireless network access point, a router, a hub, etc.). The current Wi-Fi Direct protocol is established under the regulation of an IEEE 802.11 standard and sets up steps for the peer-to-peer connection establishment between non-intermediate devices. The said steps include a Device Discovery Procedure capable of allowing wireless communication devices to discover each other, a Group Owner Negotiation (GO Negotiation) of a Group Formation Procedure capable of setting each of the wireless communication devices to be a master or a slave and a Provisioning step of the Group Formation Procedure capable of allowing the wireless communication devices to exchange their pairing rules. These procedures result in the interconnection process of Wi-Fi Direct being more complicated, failing more often and increasing the connection-establishment time. As a result, users often find Wi-Fi Direct unfriendly in usage.
In detail, the Device Discovery Procedure in Wi-Fi Direct protocol includes a Listen State, a Scan State and a Find Phase. The Listen State allows a wireless communication device to enter a state of being discoverable. For instance, in a case that the communication frequency band is located at 2.4 GHz, the Wi-Fi Direct Protocol defines the wireless channels 1, 6, 11 in this frequency band as social channels. A wireless communication device is obligated to choose one of the three channels as the social channel for itself and to periodically jump to the social channel from a current channel in the Listen State so as to wait for the call and query from other wireless communication devices. The wireless communication device can also visit every channel in the frequency band during the Scan State so as to find out whether a linkable wireless communication device exists, and the search means may not only include a general scan procedure in compliance with a 802.11 standard but also a procedure for searching devices in support of the Wi-Fi Direct Protocol. The wireless communication device is further able to go to the social channel in the Find Phase to find out other wireless communication devices for pairing. Accordingly, once a wireless communication device enters the Device Discovery Procedure, the wireless communication device switches between the above-mentioned three states. This series of actions is iterative and complicated and probably makes two wireless communication devices unable to discover each other due to their frequency jumps (or called frequency hopping). Even though two wireless communication devices are paired successfully, the frequency jumps from the start of the Device Discovery Procedure to the beginning of peer-to-peer connection could make the connection between the two devices unstable or consume too much time in the establishment of the previous or new connection.
In addition, as to the GO Negotiation of the Group Formation Procedure, the Wi-Fi Direct Protocol sets a rule to determine the master-slave relationship between link partners through an exchange of three packets. The three packets are GO Negotiation Request, GO Negotiation Response and GO Negotiation Confirmation respectively. More specifically, the wireless communication device informs its link object of its intention of being a group owner (i.e. the master in a link relationship) through a packet carrying a GO intent, and the device who has a stronger intention becomes the group owner. If the intentions of the two link objects are the same, a Tie Breaker rule is executed to make arbitration. But if both the two link objects claim their GO intent with the highest value, which means that none of the two sides compromises, the negotiation breaks down, and the connection is not established. The above-mentioned negotiation process needs the exchange of three packets so as to determine the master-slave relationship Due to the poor environment of the wireless transmission, the above-mentioned negotiation process probably consumes a lot of time or fails to connect when some transmission is lost or retransmitted during the packet exchange process. Moreover, if both the two link objects claim the highest GO intent, this negotiation process is unable to prevent the negotiation from breaking down, which leads to a connection failure.
People who are interested in the detail of Wi-Fi Direct may refer to the standard of Wi-Fi Alliance.